/**
 * data-structure-typed
 *
 * @author Pablo Zeng
 * @copyright Copyright (c) 2022 Pablo Zeng <zrwusa@gmail.com>
 * @license MIT License
 */
import type { Comparator, DFSOrderPattern, ElementCallback, HeapOptions } from '../../types';
import { IterableElementBase } from '../base';
/**
 * Binary heap with pluggable comparator; supports fast insertion and removal of the top element.
 * @remarks Typical operations: O(log N) insert/remove, O(1) peek. Space O(N).
 * @template E
 * @template R
 * 1. Complete Binary Tree: Heaps are typically complete binary trees, meaning every level is fully filled except possibly for the last level, which has nodes as far left as possible.
 * 2. Heap Properties: Each node in a heap follows a specific order property, which varies depending on the type of heap:
 * Max Heap: The value of each parent node is greater than or equal to the value of its children.
 * Min Heap: The value of each parent node is less than or equal to the value of its children.
 * 3. Root Node Access: In a heap, the largest element (in a max heap) or the smallest element (in a min heap) is always at the root of the tree.
 * 4. Efficient Insertion and Deletion: Due to its structure, a heap allows for insertion and deletion operations in logarithmic time (O(log n)).
 * 5. Managing Dynamic Data Sets: Heaps effectively manage dynamic data sets, especially when frequent access to the largest or smallest elements is required.
 * 6. Non-linear Search: While a heap allows rapid access to its largest or smallest element, it is less efficient for other operations, such as searching for a specific element, as it is not designed for these tasks.
 * 7. Efficient Sorting Algorithms: For example, heap sort. Heap sort uses the properties of a heap to sort elements.
 * 8. Graph Algorithms: Such as Dijkstra's shortest path algorithm and Prime's minimum-spanning tree algorithm, which use heaps to improve performance.
 * @example
 * // Use Heap to solve top k problems
 *  function topKElements(arr: number[], k: number): number[] {
 *       const heap = new Heap<number>([], { comparator: (a, b) => b - a }); // Max heap
 *       arr.forEach(num => {
 *         heap.add(num);
 *         if (heap.size > k) heap.poll(); // Keep the heap size at K
 *       });
 *       return heap.toArray();
 *     }
 *
 *     const numbers = [10, 30, 20, 5, 15, 25];
 *     console.log(topKElements(numbers, 3)); // [15, 10, 5];
 * @example
 * // Use Heap to dynamically maintain the median
 *  class MedianFinder {
 *       private low: MaxHeap<number>; // Max heap, stores the smaller half
 *       private high: MinHeap<number>; // Min heap, stores the larger half
 *
 *       constructor() {
 *         this.low = new MaxHeap<number>([]);
 *         this.high = new MinHeap<number>([]);
 *       }
 *
 *       addNum(num: number): void {
 *         if (this.low.isEmpty() || num <= this.low.peek()!) this.low.add(num);
 *         else this.high.add(num);
 *
 *         // Balance heaps
 *         if (this.low.size > this.high.size + 1) this.high.add(this.low.poll()!);
 *         else if (this.high.size > this.low.size) this.low.add(this.high.poll()!);
 *       }
 *
 *       findMedian(): number {
 *         if (this.low.size === this.high.size) return (this.low.peek()! + this.high.peek()!) / 2;
 *         return this.low.peek()!;
 *       }
 *     }
 *
 *     const medianFinder = new MedianFinder();
 *     medianFinder.addNum(10);
 *     console.log(medianFinder.findMedian()); // 10;
 *     medianFinder.addNum(20);
 *     console.log(medianFinder.findMedian()); // 15;
 *     medianFinder.addNum(30);
 *     console.log(medianFinder.findMedian()); // 20;
 *     medianFinder.addNum(40);
 *     console.log(medianFinder.findMedian()); // 25;
 *     medianFinder.addNum(50);
 *     console.log(medianFinder.findMedian()); // 30;
 * @example
 * // Use Heap for load balancing
 *  function loadBalance(requests: number[], servers: number): number[] {
 *       const serverHeap = new Heap<{ id: number; load: number }>([], { comparator: (a, b) => a.load - b.load }); // min heap
 *       const serverLoads = new Array(servers).fill(0);
 *
 *       for (let i = 0; i < servers; i++) {
 *         serverHeap.add({ id: i, load: 0 });
 *       }
 *
 *       requests.forEach(req => {
 *         const server = serverHeap.poll()!;
 *         serverLoads[server.id] += req;
 *         server.load += req;
 *         serverHeap.add(server); // The server after updating the load is re-entered into the heap
 *       });
 *
 *       return serverLoads;
 *     }
 *
 *     const requests = [5, 2, 8, 3, 7];
 *     console.log(loadBalance(requests, 3)); // [12, 8, 5];
 * @example
 * // Use Heap to schedule tasks
 *  type Task = [string, number];
 *
 *     function scheduleTasks(tasks: Task[], machines: number): Map<number, Task[]> {
 *       const machineHeap = new Heap<{ id: number; load: number }>([], { comparator: (a, b) => a.load - b.load }); // Min heap
 *       const allocation = new Map<number, Task[]>();
 *
 *       // Initialize the load on each machine
 *       for (let i = 0; i < machines; i++) {
 *         machineHeap.add({ id: i, load: 0 });
 *         allocation.set(i, []);
 *       }
 *
 *       // Assign tasks
 *       tasks.forEach(([task, load]) => {
 *         const machine = machineHeap.poll()!;
 *         allocation.get(machine.id)!.push([task, load]);
 *         machine.load += load;
 *         machineHeap.add(machine); // The machine after updating the load is re-entered into the heap
 *       });
 *
 *       return allocation;
 *     }
 *
 *     const tasks: Task[] = [
 *       ['Task1', 3],
 *       ['Task2', 1],
 *       ['Task3', 2],
 *       ['Task4', 5],
 *       ['Task5', 4]
 *     ];
 *     const expectedMap = new Map<number, Task[]>();
 *     expectedMap.set(0, [
 *       ['Task1', 3],
 *       ['Task4', 5]
 *     ]);
 *     expectedMap.set(1, [
 *       ['Task2', 1],
 *       ['Task3', 2],
 *       ['Task5', 4]
 *     ]);
 *     console.log(scheduleTasks(tasks, 2)); // expectedMap;
 * @example
 * // Get all elements as array
 *  const heap = new Heap<number>([5, 1, 3, 2, 4]);
 *     const arr = heap.toArray();
 *     console.log(arr.length); // 5;
 *     console.log(arr.sort()); // [1, 2, 3, 4, 5];
 */
export declare class Heap<E = any, R = any> extends IterableElementBase<E, R> {
    protected _equals: (a: E, b: E) => boolean;
    /**
     * Create a Heap and optionally bulk-insert elements.
     * @remarks Time O(N), Space O(N)
     * @param [elements] - Iterable of elements (or raw values if toElementFn is set).
     * @param [options] - Options such as comparator and toElementFn.
     * @returns New Heap instance.
     */
    constructor(elements?: Iterable<E | R>, options?: HeapOptions<E, R>);
    protected _elements: E[];
    /**
     * Get the backing array of the heap.
     * @remarks Time O(1), Space O(1)
     * @returns Internal elements array.
     */
    get elements(): E[];
    /**
     * Get the number of elements.
     * @remarks Time O(1), Space O(1)
     * @returns Heap size.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Track heap capacity
   *  const heap = new Heap<number>();
   *     console.log(heap.size); // 0;
   *     heap.add(10);
   *     heap.add(20);
   *     console.log(heap.size); // 2;
   *     heap.poll();
   *     console.log(heap.size); // 1;
     */
    get size(): number;
    /**
     * Get the last leaf element.
     * @remarks Time O(1), Space O(1)
     * @returns Last element or undefined.
     */
    get leaf(): E | undefined;
    /**
     * Create a heap of the same class from an iterable.
     * @remarks Time O(N), Space O(N)
     * @template T
     * @template R
     * @template S
     * @param [elements] - Iterable of elements or raw records.
     * @param [options] - Heap options including comparator.
     * @returns A new heap instance of this class.
     */
    static from<T, R = any, S extends Heap<T, R> = Heap<T, R>>(this: new (elements?: Iterable<T | R>, options?: HeapOptions<T, R>) => S, elements?: Iterable<T | R>, options?: HeapOptions<T, R>): S;
    /**
     * Build a Heap from an iterable in linear time given a comparator.
     * @remarks Time O(N), Space O(N)
     * @template EE
     * @template RR
     * @param elements - Iterable of elements.
     * @param options - Heap options including comparator.
     * @returns A new Heap built from elements.
     */
    static heapify<EE = any, RR = any>(elements: Iterable<EE>, options: HeapOptions<EE, RR>): Heap<EE, RR>;
    /**
     * Insert an element.
     * @remarks Time O(log N) amortized, Space O(1)
     * @param element - Element to insert.
     * @returns True.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // basic Heap creation and add operation
   *  // Create a min heap (default)
   *     const minHeap = new Heap([5, 3, 7, 1, 9, 2]);
   *
   *     // Verify size
   *     console.log(minHeap.size); // 6;
   *
   *     // Add new element
   *     minHeap.add(4);
   *     console.log(minHeap.size); // 7;
   *
   *     // Min heap property: smallest element at root
   *     const min = minHeap.peek();
   *     console.log(min); // 1;
     */
    add(element: E): boolean;
    /**
     * Insert many elements from an iterable.
     * @remarks Time O(N log N), Space O(1)
     * @param elements - Iterable of elements or raw values.
     * @returns Array of per-element success flags.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Add multiple elements
   *  const heap = new Heap<number>([], { comparator: (a, b) => a - b });
   *     heap.addMany([5, 3, 7, 1]);
   *     console.log(heap.peek()); // 1;
   *     console.log(heap.size); // 4;
     */
    addMany(elements: Iterable<E | R>): boolean[];
    /**
     * Remove and return the top element.
     * @remarks Time O(log N), Space O(1)
     * @returns Top element or undefined.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Heap with custom comparator (MaxHeap behavior)
   *  interface Task {
   *       id: number;
   *       priority: number;
   *       name: string;
   *     }
   *
   *     // Custom comparator for max heap behavior (higher priority first)
   *     const tasks: Task[] = [
   *       { id: 1, priority: 5, name: 'Email' },
   *       { id: 2, priority: 3, name: 'Chat' },
   *       { id: 3, priority: 8, name: 'Alert' }
   *     ];
   *
   *     const maxHeap = new Heap(tasks, {
   *       comparator: (a: Task, b: Task) => b.priority - a.priority
   *     });
   *
   *     console.log(maxHeap.size); // 3;
   *
   *     // Peek returns highest priority task
   *     const topTask = maxHeap.peek();
   *     console.log(topTask?.priority); // 8;
   *     console.log(topTask?.name); // 'Alert';
     */
    /**
     * @deprecated Use `pop` instead. Will be removed in a future major version.
     
     
     
      * @example
   * // Heap with custom comparator (MaxHeap behavior)
   *  interface Task {
   *       id: number;
   *       priority: number;
   *       name: string;
   *     }
   *
   *     // Custom comparator for max heap behavior (higher priority first)
   *     const tasks: Task[] = [
   *       { id: 1, priority: 5, name: 'Email' },
   *       { id: 2, priority: 3, name: 'Chat' },
   *       { id: 3, priority: 8, name: 'Alert' }
   *     ];
   *
   *     const maxHeap = new Heap(tasks, {
   *       comparator: (a: Task, b: Task) => b.priority - a.priority
   *     });
   *
   *     console.log(maxHeap.size); // 3;
   *
   *     // Peek returns highest priority task
   *     const topTask = maxHeap.peek();
   *     console.log(topTask?.priority); // 8;
   *     console.log(topTask?.name); // 'Alert';
     */
    poll(): E | undefined;
    /**
     * Remove and return the top element (min or max depending on comparator).
     * @remarks Time O(log N) amortized, Space O(1)
     * @returns The removed top element, or undefined if empty.
     */
    pop(): E | undefined;
    /**
     * Get the current top element without removing it.
     * @remarks Time O(1), Space O(1)
     * @returns Top element or undefined.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Heap for event processing with priority
   *  interface Event {
   *       id: number;
   *       type: 'critical' | 'warning' | 'info';
   *       timestamp: number;
   *       message: string;
   *     }
   *
   *     // Custom priority: critical > warning > info
   *     const priorityMap = { critical: 3, warning: 2, info: 1 };
   *
   *     const eventHeap = new Heap<Event>([], {
   *       comparator: (a: Event, b: Event) => {
   *         const priorityA = priorityMap[a.type];
   *         const priorityB = priorityMap[b.type];
   *         return priorityB - priorityA; // Higher priority first
   *       }
   *     });
   *
   *     // Add events in random order
   *     eventHeap.add({ id: 1, type: 'info', timestamp: 100, message: 'User logged in' });
   *     eventHeap.add({ id: 2, type: 'critical', timestamp: 101, message: 'Server down' });
   *     eventHeap.add({ id: 3, type: 'warning', timestamp: 102, message: 'High memory' });
   *     eventHeap.add({ id: 4, type: 'info', timestamp: 103, message: 'Cache cleared' });
   *     eventHeap.add({ id: 5, type: 'critical', timestamp: 104, message: 'Database error' });
   *
   *     console.log(eventHeap.size); // 5;
   *
   *     // Process events by priority (critical first)
   *     const processedOrder: Event[] = [];
   *     while (eventHeap.size > 0) {
   *       const event = eventHeap.poll();
   *       if (event) {
   *         processedOrder.push(event);
   *       }
   *     }
   *
   *     // Verify critical events came first
   *     console.log(processedOrder[0].type); // 'critical';
   *     console.log(processedOrder[1].type); // 'critical';
   *     console.log(processedOrder[2].type); // 'warning';
   *     console.log(processedOrder[3].type); // 'info';
   *     console.log(processedOrder[4].type); // 'info';
   *
   *     // Verify O(log n) operations
   *     const newHeap = new Heap<number>([5, 3, 7, 1]);
   *
   *     // Add - O(log n)
   *     newHeap.add(2);
   *     console.log(newHeap.size); // 5;
   *
   *     // Poll - O(log n)
   *     const removed = newHeap.poll();
   *     console.log(removed); // 1;
   *
   *     // Peek - O(1)
   *     const top = newHeap.peek();
   *     console.log(top); // 2;
     */
    peek(): E | undefined;
    /**
     * Check whether the heap is empty.
     * @remarks Time O(1), Space O(1)
     * @returns True if size is 0.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Check if heap is empty
   *  const heap = new Heap<number>([], { comparator: (a, b) => a - b });
   *     console.log(heap.isEmpty()); // true;
   *     heap.add(1);
   *     console.log(heap.isEmpty()); // false;
     */
    isEmpty(): boolean;
    /**
     * Remove all elements.
     * @remarks Time O(1), Space O(1)
     * @returns void
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Remove all elements
   *  const heap = new Heap<number>([1, 2, 3], { comparator: (a, b) => a - b });
   *     heap.clear();
   *     console.log(heap.isEmpty()); // true;
     */
    clear(): void;
    /**
     * Check if an equal element exists in the heap.
     * @remarks Time O(N), Space O(1)
     * @param element - Element to search for.
     * @returns True if found.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Check element existence
   *  const heap = new Heap<number>([3, 1, 2], { comparator: (a, b) => a - b });
   *     console.log(heap.has(1)); // true;
   *     console.log(heap.has(99)); // false;
     */
    has(element: E): boolean;
    /**
     * Delete one occurrence of an element.
     * @remarks Time O(N), Space O(1)
     * @param element - Element to delete.
     * @returns True if an element was removed.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Remove specific element
   *  const heap = new Heap<number>([3, 1, 4, 1, 5], { comparator: (a, b) => a - b });
   *     heap.delete(4);
   *     console.log(heap.toArray().includes(4)); // false;
     */
    delete(element: E): boolean;
    /**
     * @deprecated Use `deleteWhere` instead. Will be removed in a future major version.
     */
    deleteBy(predicate: (element: E, index: number, heap: this) => boolean): boolean;
    /**
     * Delete the first element that matches a predicate.
     * @remarks Time O(N), Space O(1)
     * @param predicate - Function (element, index, heap) → boolean.
     * @returns True if an element was removed.
     */
    deleteWhere(predicate: (element: E, index: number, heap: this) => boolean): boolean;
    /**
     * Set the equality comparator used by has/delete operations.
     * @remarks Time O(1), Space O(1)
     * @param equals - Equality predicate (a, b) → boolean.
     * @returns This heap.
     */
    setEquality(equals: (a: E, b: E) => boolean): this;
    /**
     * Traverse the binary heap as a complete binary tree and collect elements.
     * @remarks Time O(N), Space O(H)
     * @param [order] - Traversal order: 'PRE' | 'IN' | 'POST'.
     * @returns Array of visited elements.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Depth-first traversal
   *  const heap = new Heap<number>([3, 1, 2], { comparator: (a, b) => a - b });
   *     const result = heap.dfs('IN');
   *     console.log(result.length); // 3;
     */
    dfs(order?: DFSOrderPattern): E[];
    /**
     * Restore heap order bottom-up (heapify in-place).
     * @remarks Time O(N), Space O(1)
     * @returns Array of per-node results from fixing steps.
     */
    fix(): boolean[];
    /**
     * Return all elements in ascending order by repeatedly polling.
     * @remarks Time O(N log N), Space O(N)
     * @returns Sorted array of elements.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Sort elements using heap
   *  const heap = new Heap<number>([5, 1, 3, 2, 4]);
   *     const sorted = heap.sort();
   *     console.log(sorted); // [1, 2, 3, 4, 5];
     */
    sort(): E[];
    /**
     * Deep clone this heap.
     * @remarks Time O(N), Space O(N)
     * @returns A new heap with the same elements.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Create independent copy
   *  const heap = new Heap<number>([3, 1, 4], { comparator: (a, b) => a - b });
   *     const copy = heap.clone();
   *     copy.poll();
   *     console.log(heap.size); // 3;
   *     console.log(copy.size); // 2;
     */
    clone(): this;
    /**
     * Filter elements into a new heap of the same class.
     * @remarks Time O(N log N), Space O(N)
     * @param callback - Predicate (element, index, heap) → boolean to keep element.
     * @param [thisArg] - Value for `this` inside the callback.
     * @returns A new heap with the kept elements.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Filter elements
   *  const heap = new Heap<number>([1, 2, 3, 4, 5], { comparator: (a, b) => a - b });
   *     const evens = heap.filter(x => x % 2 === 0);
   *     console.log(evens.size); // 2;
     */
    filter(callback: ElementCallback<E, R, boolean>, thisArg?: unknown): this;
    /**
     * Map elements into a new heap of possibly different element type.
     * @remarks Time O(N log N), Space O(N)
     * @template EM
     * @template RM
     * @param callback - Mapping function (element, index, heap) → newElement.
     * @param options - Options for the output heap, including comparator for EM.
     * @param [thisArg] - Value for `this` inside the callback.
     * @returns A new heap with mapped elements.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
      * @example
   * // Transform elements
   *  const heap = new Heap<number>([1, 2, 3], { comparator: (a, b) => a - b });
   *     const doubled = heap.map(x => x * 2, { comparator: (a, b) => a - b });
   *     console.log(doubled.peek()); // 2;
     */
    map<EM, RM>(callback: ElementCallback<E, R, EM>, options: HeapOptions<EM, RM> & {
        comparator: Comparator<EM>;
    }, thisArg?: unknown): Heap<EM, RM>;
    /**
     * Map elements into a new heap of the same element type.
     * @remarks Time O(N log N), Space O(N)
     * @param callback - Mapping function (element, index, heap) → element.
     * @param [thisArg] - Value for `this` inside the callback.
     * @returns A new heap with mapped elements.
     */
    mapSame(callback: ElementCallback<E, R, E>, thisArg?: unknown): this;
    protected readonly _DEFAULT_COMPARATOR: Comparator<E>;
    protected readonly _comparator: Comparator<E>;
    /**
     * Get the comparator used to order elements.
     * @remarks Time O(1), Space O(1)
     * @returns Comparator function.
     */
    get comparator(): Comparator<E>;
    protected _getIterator(): IterableIterator<E>;
    protected _bubbleUp(index: number): boolean;
    protected _sinkDown(index: number, halfLength: number): boolean;
    /**
     * (Protected) Create an empty instance of the same concrete class.
     * @remarks Time O(1), Space O(1)
     * @param [options] - Options to override comparator or toElementFn.
     * @returns A like-kind empty heap instance.
     */
    protected _createInstance(options?: HeapOptions<E, R>): this;
    /**
     * (Protected) Create a like-kind instance seeded by elements.
     * @remarks Time O(N log N), Space O(N)
     * @template EM
     * @template RM
     * @param [elements] - Iterable of elements or raw values to seed.
     * @param [options] - Options forwarded to the constructor.
     * @returns A like-kind heap instance.
     */
    protected _createLike<EM, RM>(elements?: Iterable<EM> | Iterable<RM>, options?: HeapOptions<EM, RM>): Heap<EM, RM>;
    /**
     * (Protected) Spawn an empty like-kind heap instance.
     * @remarks Time O(1), Space O(1)
     * @template EM
     * @template RM
     * @param [options] - Options forwarded to the constructor.
     * @returns An empty like-kind heap instance.
     */
    protected _spawnLike<EM, RM>(options?: HeapOptions<EM, RM>): Heap<EM, RM>;
}
/**
 * Node container used by FibonacciHeap.
 * @remarks Time O(1), Space O(1)
 * @template E
 */
export declare class FibonacciHeapNode<E> {
    element: E;
    degree: number;
    left?: FibonacciHeapNode<E>;
    right?: FibonacciHeapNode<E>;
    child?: FibonacciHeapNode<E>;
    parent?: FibonacciHeapNode<E>;
    marked: boolean;
    constructor(element: E, degree?: number);
}
/**
 * Fibonacci heap (min-heap) optimized for fast merges and amortized operations.
 * @remarks Time O(1), Space O(1)
 * @template E
 * @example examples will be generated by unit test
 */
export declare class FibonacciHeap<E> {
    /**
     * Create a FibonacciHeap.
     * @remarks Time O(1), Space O(1)
     * @param [comparator] - Comparator to order elements (min-heap by default).
     * @returns New FibonacciHeap instance.
     */
    constructor(comparator?: Comparator<E>);
    protected _root?: FibonacciHeapNode<E>;
    /**
     * Get the circular root list head.
     * @remarks Time O(1), Space O(1)
     * @returns Root node or undefined.
     */
    get root(): FibonacciHeapNode<E> | undefined;
    protected _size: number;
    get size(): number;
    protected _min?: FibonacciHeapNode<E>;
    /**
     * Get the current minimum node.
     * @remarks Time O(1), Space O(1)
     * @returns Min node or undefined.
     */
    get min(): FibonacciHeapNode<E> | undefined;
    protected readonly _comparator: Comparator<E>;
    get comparator(): Comparator<E>;
    clear(): void;
    add(element: E): boolean;
    /**
     * Push an element into the root list.
     * @remarks Time O(1) amortized, Space O(1)
     * @param element - Element to insert.
     * @returns True when the element is added.
     */
    push(element: E): boolean;
    peek(): E | undefined;
    /**
     * Collect nodes from a circular doubly linked list starting at head.
     * @remarks Time O(K), Space O(K)
     * @param [head] - Start node of the circular list.
     * @returns Array of nodes from the list.
     */
    consumeLinkedList(head?: FibonacciHeapNode<E>): FibonacciHeapNode<E>[];
    /**
     * Insert a node into a parent's child list (circular).
     * @remarks Time O(1), Space O(1)
     * @param parent - Parent node.
     * @param node - Child node to insert.
     * @returns void
     */
    mergeWithChild(parent: FibonacciHeapNode<E>, node: FibonacciHeapNode<E>): void;
    poll(): E | undefined;
    /**
     * Remove and return the minimum element, consolidating the root list.
     * @remarks Time O(log N) amortized, Space O(1)
     * @returns Minimum element or undefined.
     */
    pop(): E | undefined;
    /**
     * Meld another heap into this heap.
     * @remarks Time O(1), Space O(1)
     * @param heapToMerge - Another FibonacciHeap to meld into this one.
     * @returns void
     */
    merge(heapToMerge: FibonacciHeap<E>): void;
    createNode(element: E): FibonacciHeapNode<E>;
    isEmpty(): boolean;
    protected _defaultComparator(a: E, b: E): number;
    protected mergeWithRoot(node: FibonacciHeapNode<E>): void;
    protected removeFromRoot(node: FibonacciHeapNode<E>): void;
    protected _link(y: FibonacciHeapNode<E>, x: FibonacciHeapNode<E>): void;
    protected _consolidate(): void;
}